X-ray diffraction and electron microscopy will be used to investigate the structures of phycobilisomes. These organelles exist in cyano-bacteria and rhodophyta where their cellular role is to absorb light and to transmit the energy of that absorbed light to the chlorophyll-a containing photosynthetic apparatus. Through the use of several structural techniques -- single crystal X-ray diffraction, low angle X-ray scattering, and electron microscopy -- we hope to learn the detailed structure of the phycobilisome and from this the structural principals upon which its assembly is based. The immediate objectives are determination of the atomic resolution structures of the principal components of the phycobilisome and initiation of a program of research into phycobilisome structure through the combined use of electron microscopy and small angle X-ray scattering.